Aeromedical
Aviation accidents are mostly caused by humans, not machines — and helicopters double down on that pattern because most rotorcraft fly single-pilot in environments (low altitude, marginal weather, off-airport landings) where physiological degradation has nowhere to hide. The threats here aren't exotic: they're hypoxia, hyperventilation, the inner ear in cloud, the eye in twilight, alcohol that's still wearing off, fatigue you talked yourself out of recognizing. This section makes them visible so you can intercept yours before the aircraft pays for them.
Foundations — pre-flight self-assessment
Fundamentals & IMSAFE
The human-factor framing, the IMSAFE personal-minimums checklist, and the FARs that make self-grounding a legal duty (§ 61.53, § 91.17).
Alcohol, Drugs & Fatigue
8-hour bottle-to-throttle, the OTC drugs that quietly disqualify you, circadian rhythm and the WOCL window, and why hangover effects outlast the BAC.
Physiology in flight
Hypoxia & Altitude
Four mechanisms, four stages, FISH RIB symptoms. § 91.211 oxygen rules and Time of Useful Consciousness — why even helicopter pilots in mountainous HEMS need this.
Hyperventilation & Stress
Anxiety-induced over-breathing produces hypoxia-like symptoms with the opposite cause. Telling them apart, and why slow-and-deliberate breathing is the recovery.
CO & Environmental Stressors
Carbon monoxide via cracked heater shroud — a leading helicopter killer. Plus dehydration, heat, cold, noise, and rotor-induced vibration syndromes.
Sensory deception
Spatial Disorientation
The vestibular system is a liar without a horizon. Three SD types, the leans, somatogravic illusion, and an IIMC primer that points to the dedicated IIMC recovery page.
Vision & Illusions
Rod-cone night vision, the 30-minute dark adaptation, runway/terrain illusions on approach, and helicopter-specific killers: hover parallax, brownout, whiteout, autokinesis.